TY - JOUR AU - Máthé, Csaba AU - Beyer, Dániel AU - Erdődi, Ferenc AU - Serfőző, Zoltán József AU - Székvölgyi, Lóránt AU - Vasas, Gábor AU - Mikóné Hamvas, Márta AU - Jámbrik, K AU - Gonda, Sándor AU - Kiss, Andrea AU - Máthéné Szigeti, Zsuzsa AU - Surányi, Gyula TI - Microcystin-LR induces abnormal root development by altering microtubule organization in tissue-cultured common reed (Phragmites australis) plantlets JF - AQUATIC TOXICOLOGY J2 - AQUAT TOXICOL VL - 92 PY - 2009 IS - 3 SP - 122 EP - 130 PG - 9 SN - 0166-445X DO - 10.1016/j.aquatox.2009.02.005 UR - https://m2.mtmt.hu/api/publication/122870 ID - 122870 N1 - Chemicals/CAS: microcystin LR, 101043-37-2; Microcystins; Phosphoprotein Phosphatases, 3.1.3.16; Water Pollutants, Chemical; cyanoginosin LR, 101043-37-2 AB - Microcystin-LR (MC-LR) is a heptapeptide cyanotoxin, known to be a potent inhibitor of type 1 and 2A protein phosphatases in eukaryotes. Our aim was to investigate the effect of MC-LR on the organization of microtubules and mitotic chromatin in relation to its possible effects on cell and whole organ morphology in roots of common reed (Phragmites australis). P australis is a widespread freshwater and brackish water aquatic macrophyte, frequently exposed to phytotoxins in eutrophic waters. Reed plantlets regenerated from embryogenic calli were treated with 0.001-40 mu g ml(-1) (0.001-40.2 mu M) MC-LR for 2- 20 days. At 0.5 mu g ml(-1) MC-LR and at higher cyanotoxin concentrations, the inhibition of protein phosphatase activity by MC-LR induced alterations in reed root growth and morphology, including abnormal lateral root development and the radial swelling of cells in the elongation zone of primary and lateral roots. Both short-term (2-5 days) and long-term (10-20 days) of cyanotoxin treatment induced microtubule disruption in meristems and in the elongation and differentiation zones. Microtubule disruption was accompanied by root cell shape alteration. At concentrations of 0.5-5 mu g ml(-1), MC-LR increased mitotic index at long-term exposure and induced the increase of the percentage of meristematic cells in prophase as well as telophase and cytokinesis of late mitosis. High cyanotoxin concentrations (10-40 mu g ml(-1)) inhibited mitosis at as short as 2 days of exposure. The alteration of microtubule organization was observed in mitotic cells at all exposure periods studied, at cyanotoxin concentrations of 0.5-40 mu g ml(-1). MC-LR induced spindle anomalies at the meta phase- anaphase transition, the formation of asymmetric anaphase spindles and abnormal sister chromatid separation. This paper reports for the first time that MC-LR induces cytoskeletal changes that lead to alterations of root architecture and development in common reed and generally, in plant cells. The MC-LR induced alterations in cells of an ecologically important aquatic macrophyte can reveal the importance of the effects of a cyanobacterial toxin in aquatic ecosystems. (C) 2009 Elsevier B.V. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Vehovszky, Ágnes AU - Ács, András AU - Kovács, Attila AU - Szabó, H AU - Győri, János AU - Farkas, Anna TI - Isolated strains of Cylindrospermopsis raciborskii from Lake Balaton (Hungary) produce anatoxin-a like neurotoxins JF - COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY J2 - COMP BIOCHEM PHYS A VL - 153 PY - 2009 IS - Suppl.1. SP - S88 SN - 1095-6433 DO - 10.1016/j.cbpa.2009.04.083 UR - https://m2.mtmt.hu/api/publication/1268939 ID - 1268939 AB - The membrane effects of the partially purified extracts (from 100 mg of freeze-dried material) of the cyanobacteria Cylindrospermopsis raciborskii ACT 9502, ACT 9504, ACT 9505 isolated from Lake Balaton, Hungary were characterized on identified central neurons of the pond snail Lymnaea stagnalis. The toxic pattern of solid phase extracted fractions was screened against the partially purified anatoxins produced by the positive reference strain Oscillatoria formosa (PCC 6506). The purified fraction of PCC 6506 strain (1 mg dry weight/ml) evoked strong intracellular (either depolarizing or hyperpolarizing) membrane responses on the identified neurons (buccal B1, B4 neurons, the pedal RPeD1 neuron), similar to the locally applied acetylcholine, iontophoretically injected near the surface of the cell body. PCC 6506 applied by perfusion in lower (0.2–0.5 mg/ml) concentration reversibly blocked this acetylcholine responses, suggesting inhibition of the cholinergic receptors. The similar reversible, dose-dependent inhibition of acetylcholine responses was recorded in the presence of the authentic neurotoxin anatoxin-a (1–10 µM) applied by perfusion. The extracts prepared from Cylindrospermopsis raciborskii (ACT 9502, ACT 9505) had similar cholinergic agonist effect as well as blocking the acetylcholine responses suggesting an anatoxin-a like component produced by the strains isolated from Lake Balaton. Liquid chromatography-mass spectrometry (LC-MS) confirmed the presence of the cyanotoxins anatoxin-a and homoanatoxin-a in relevant amounts in the PCC 6506 strain, and in trace amounts in the cyanobacterial mats of Cylindrospermopsis raciborskii strains isolated from Lake Balaton. This work was supported by the Hungary OTKA grant K63451. LA - English DB - MTMT ER - TY - JOUR AU - Hiripi, László AU - Nagy, L AU - Kalmár, Tibor AU - Kovács, Attila AU - Vörös, Lajos TI - Insect (Locusta migratoria migratorioides) test monitoring the toxicity of Cyanobacteria JF - NEUROTOXICOLOGY J2 - NEUROTOXICOLOGY VL - 19 PY - 1998 IS - 4-5 SP - 605 EP - 608 PG - 4 SN - 0161-813X UR - https://m2.mtmt.hu/api/publication/1138620 ID - 1138620 AB - An insect test was developed to investigate the toxicity of cyanobacteria. The African locust, Locusta migratoria migratorioides R.F. was used as a test animal instead of mouse. The cyanobacteria tested were Aphanizomenon flos-aque, Anabaena aphanizomenoides, Cylindrospermopsis raciborskii, Microcystis aeruginosa. The toxicity of authentic microcystin-LR was also tested. Cyanobacteria producing toxins killed the animals when the homogenized cell suspension was injected into the animals. The locust test proved to be more sensitive than the mouse test. The LD50 values of the different cyanobacteria for locusts and for mice, respectively were the following: 90 mu g/animal (60 mg/kg) and 8000 mu g/animal (320 mg/kg), for Aphanizomenon flos-aquae; 255 mu g/animal (170.2 mg/kg) and 3750 mu g/animal (150 mg/kg), for Anabaena aphanizomenoides; 195 mu g/animal (131.4 mg/kg) and 5750 mu g/animal (230 m/kg) for Cylindrospermopsis raciborskii; 22.5 mu g/animal (15 mg/kg) and 6000 mu g/animal (240 mg/kg), for Microcystis aeruginosa.. In locusts the LD50 value for authentic microcystin-LR was 0.2 mu g/animal (130 mg/kg). Since the weight of the mice is 15 to 20 times larger than that of the locusts, hence less toxic cells are needed to kill the locusts. The locust test is cheaper than the mouse test, large number of animals can be used in the experiments and the LD50 values can be estimated more precisely. The toxicity of C. raciborskii was significantly lower when the lyophilized cells were extracted in methanol (LD50 = 767 mg/kg), instead of NaCl solution (LD50 = 131.4 mg/kg). LA - English DB - MTMT ER -